1. Field of the Invention
The present invention relates to a damper device and a high pressure pump having the same.
2. Description of Related Art
In a case of a known high pressure pump for an internal combustion engine of a vehicle, fuel is pumped to the high pressure pump from a fuel pump, which is placed in a fuel tank, through a low pressure fuel conduit. Then, the high pressure pump pressurizes the received fuel through reciprocating movement of a plunger and then discharges the pressurized fuel toward injectors.
In the high pressure pump of this kind, a portion of the fuel in the pressurizing chamber, in which the fuel is pressurized by the plunger, is discharged to a fluid chamber that is provided at a fuel inlet side. A damper device, which includes a damper member, is placed in the fluid chamber to reduce the pressure pulsation that is generated by the fuel discharged into the fluid chamber.
In a case of another damper device disclosed in Japanese Patent No. 3823060 B2 (corresponding to US 2003/0164161 A1), a damper member, which includes two metal diaphragms, is placed in a fluid chamber and is urged between a cover member and a housing.
In a case of a damper device disclosed in Japanese Patent No. 4036153 B2 (corresponding to US 2005/0019188 A1), a damper member, which includes two metal diaphragms, is installed in a fluid chamber and is secured by components, such as a wavy spring, a washer guide and a washer.
However, in the case of Japanese Patent No. 3823060 B2, it is difficult to form a sufficient space for conducting the fuel at a location radially outward of the damper member. The fuel, which is discharged from the pressurizing chamber, flows toward the fuel inlet upon flowing along a surface of the damper member on one side of the damper member. Therefore, a sufficient pressure pulsation reducing performance of the damper member may possibly not be implemented.
The wavy spring has the following characteristic. That is, when the wavy spring is axially pressed, the wavy spring radially outwardly expands. Thus, in the case of Japanese Patent No. 3823060 B2, the radially outward displacement (expansion) of the wavy spring may be limited by the inner wall of the fluid chamber. Therefore, a uniform load may not be applied from the wavy spring to the damper member to cause torsion or twist of the damper member, and thereby it may possibly be difficult to achieve the sufficient pressure pulsation reducing performance of the damper member.
In the case of the damper device of Japanese Patent No. 4036153 B2, the number of components, which are required to install the damper member in the fuel chamber, is disadvantageously increased.